21. November 2019
Mars Express mission

Glaciers as land­scape sculp­tors – the mesas of Deuteronilus Men­sae

View of the northern part of the Deuteronilus Mensae region
View of the north­ern part of the Deuteronilus Men­sae re­gion
Image 1/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

View of the northern part of the Deuteronilus Mensae region

In­di­vid­u­al mesas up to 30 kilo­me­tres across rise as ‘out­liers’ from the plain in the tran­si­tion zone from the Mar­tian high­lands fur­ther south (left) to the north­ern low­lands (right). Deuteronilus Men­sae is a very typ­i­cal re­gion for this ‘di­choto­my bound­ary’ on Mars. The 2000-me­tre-tall moun­tains show that the Mars high­lands pre­vi­ous­ly ex­tend­ed fur­ther north but were large­ly flat­tened by ero­sive pro­cess­es. Glacial ice and flow­ing wa­ter car­ried high­land de­bris north­wards in­to the low­lands. Traces of the glacia­tions can be seen par­tic­u­lar­ly well be­tween the mesas, in the form of var­i­ous lin­ear struc­tures.
Mesas and heavily eroded craters in Deuteronilus Mensae
Mesas and heav­i­ly erod­ed craters in Deuteronilus Men­sae
Image 2/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Mesas and heavily eroded craters in Deuteronilus Mensae

The frag­men­ta­tion and ero­sion of the old high­land area left be­hind dif­fer­ent large mesas. Their plateau-like sur­faces rep­re­sent the rem­nants of a land sur­face that once ex­tend­ed much fur­ther north. There have prob­a­bly been sev­er­al phas­es of glacia­tion. Some im­pact craters in the re­gion, like the one on the left-hand side of this im­age, have heav­i­ly erod­ed rims and have been com­plete­ly filled by de­bris de­posit­ed in them. This crater is now bare­ly recog­nis­able as a cir­cu­lar struc­ture.
Signs of former glaciation in Deuteronilus Mensae
Signs of for­mer glacia­tion in Deuteronilus Men­sae
Image 3/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Signs of former glaciation in Deuteronilus Mensae

The ter­rain be­tween the mesas is even­ly cov­ered by de­posits whose sur­face tex­tures in places in­di­cate a slow, vis­cous down­ward move­ment of a mix­ture of de­bris and ice. Flow struc­tures vis­i­ble in the cen­tre of the im­age re­sem­ble glaciers com­plete­ly cov­ered with de­bris, as they oc­cur on Earth in cold cli­mat­ic re­gions such as Antarc­ti­ca.
Image Detail 1: Remnants of glaciations in Deuteronilus Mensae
Im­age De­tail 1: Rem­nants of glacia­tions in Deuteronilus Men­sae
Image 4/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Image Detail 1: Remnants of glaciations in Deuteronilus Mensae

Nu­mer­ous signs of for­mer glacia­tions, such as the struc­ture in the cen­tre of this im­age, can be seen in the plains be­tween the 1000- to 2000-me­tre-high mesas in Deuteronilus Men­sae. This is a glacier cov­ered by rock de­bris. Radar mea­sure­ments have shown that there is still ice be­neath the vis­i­ble sur­face, pro­tect­ed from sub­li­ma­tion (the di­rect tran­si­tion from a sol­id to a gaseous state) by the cov­er­ing of rock de­bris. The plateaus in the left and right thirds of the im­age al­so orig­i­nate from ice, which be­gan to flow slow­ly and plas­ti­cal­ly un­der its own weight and the ad­di­tion­al sed­i­ment load. As a re­sult, the de­bris aprons at the foot of the slopes were car­ried away from the mesas.
Image Detail 2: Impact crater filled with sediment
Im­age De­tail 2: Im­pact crater filled with sed­i­ment
Image 5/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Image Detail 2: Impact crater filled with sediment

Most of the im­pact craters in the re­gion have heav­i­ly erod­ed rims and have been al­most com­plete­ly filled with de­posit­ed ma­te­ri­al car­ried from else­where, as can be clear­ly seen in this ex­am­ple. In places, the craters are still ev­i­dent as cir­cu­lar struc­tures with flat bases. In this un­named crater, which is 20 kilo­me­tres in di­am­e­ter, on­ly the top of the cen­tral peak pro­trudes above the sed­i­ment.
Image Detail 3: Glacial flow structures between mesas
Im­age De­tail 3: Glacial flow struc­tures be­tween mesas
Image 6/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Image Detail 3: Glacial flow structures between mesas

Traces of ero­sion, trans­porta­tion and de­po­si­tion of rock from the south­ern Mar­tian high­lands by slow­ly mov­ing glaciers can be seen through­out the low­lands and val­leys be­tween the mesas of Deuteronilus Men­sae. The tex­ture of the sur­face in­di­cates the di­rec­tion of flow and the changes in di­rec­tion caused by to­po­graph­i­cal ob­sta­cles, which ‘steered’ the glacier. In the cen­tre of the im­age, an im­pact crater ap­prox­i­mate­ly 10 kilo­me­tres in di­am­e­ter is vis­i­ble. Its bowl-shaped struc­ture has been com­plete­ly lev­elled by sed­i­ment de­posits up to the rem­nants of the crater rim.
Image Detail 4: Concentric deposits around the mesas
Im­age De­tail 4: Con­cen­tric de­posits around the mesas
Image 7/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Image Detail 4: Concentric deposits around the mesas

The ter­rain be­tween the mesas is cov­ered by de­posits in many places. The sur­face tex­ture of these de­posits in­di­cates a slow, vis­cous down­ward move­ment of a mix­ture of de­bris and ice. The con­cen­tric lo­bate de­bris aprons around the plateaus re­sem­ble rock glaciers or glaciers com­plete­ly cov­ered with de­bris, as they oc­cur on earth in Antarc­ti­ca, for ex­am­ple. The sur­face pat­terns formed by the glacier as it de­posit­ed its de­bris and rub­ble re­flect the dif­fer­ent flow ve­loc­i­ties of the un­der­ly­ing vis­cous ice. Radar ob­ser­va­tions sug­gest that there is still ice un­der this rock blan­ket to­day, even if it is not vis­i­ble. If ice is cov­ered by rocky de­bris, it is like­ly to be pro­tect­ed from sub­li­ma­tion (the tran­si­tion from sol­id to gaseous state) for an ex­ten­sive pe­ri­od.
Image Detail 5: Fracture structures of glacial ice in Deuteronilus Mensae
Im­age De­tail 5: Frac­ture struc­tures of glacial ice in Deuteronilus Men­sae
Image 8/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Image Detail 5: Fracture structures of glacial ice in Deuteronilus Mensae

The glacial struc­tures in Deuteronilus Men­sae have led some sci­en­tists to as­sume the ex­is­tence of glaciers here in ge­o­log­i­cal­ly re­cent times – be­tween 100,000 and 10,000 years ago. Large-area glacia­tions are like­ly to have oc­curred in ice ages sim­i­lar to those on Earth, even at mid-lat­i­tudes. Ice may still be present to­day be­low the rocks and the boul­ders that cov­ered the slow­ly flow­ing glaciers. Ob­ser­va­tions made with the Shal­low Radar (SHARAD) in­stru­ment on NASA’s Mars Re­con­nais­sance Or­biter seem to con­firm this the­o­ry.
Deuteronilus Mensae, Mars – transition zone between the highlands and lowlands
Deuteronilus Men­sae, Mars – tran­si­tion zone be­tween the high­lands and low­lands
Image 9/11, Credit: NASA/JPL (MOLA), FU Berlin

Deuteronilus Mensae, Mars – transition zone between the highlands and lowlands

Deuteronilus Men­sae is a re­gion of Mars that is ap­prox­i­mate­ly the size of Ger­many. It forms a strik­ing tran­si­tion at the Mar­tian di­choto­my bound­ary be­tween the south­ern high­lands and the plains of the north, 1000-2000 me­tres be­low. This tran­si­tion zone is char­ac­terised by nu­mer­ous mesas, rem­nants of the ero­sion that stretched to the south. To­day, these pro­trude from the land­scape as ‘out­liers’, bear­ing tes­ti­mo­ny to this ero­sion. The da­ta used to cre­ate the im­ages of this re­gion were ac­quired by the High Res­o­lu­tion Stereo Cam­era (HRSC) on 25 Febru­ary 2018 dur­ing or­bit 17,913 of ESA’s Mars Ex­press space­craft. The land­scapes shown here are lo­cat­ed in the in­ner rect­an­gle, which cov­ers an area of 170 by 65 kilo­me­tres.
Topographic image map of the northern part of Deuteronilus Mensae
To­po­graph­ic im­age map of the north­ern part of Deuteronilus Men­sae
Image 10/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Topographic image map of the northern part of Deuteronilus Mensae

Sci­en­tists from DLR and Freie Uni­ver­sität Berlin de­rive dig­i­tal ter­rain mod­els of the sur­face of Mars from the im­age strips ac­quired by the High Res­o­lu­tion Stereo Cam­era (HRSC) on the Mars Ex­press space­craft, which are record­ed from dif­fer­ent an­gles. The colour cod­ing of the dig­i­tal ter­rain mod­el (leg­end top right) pro­vides in­for­ma­tion about the dif­fer­ences in al­ti­tude in the re­gion. The plateaus of the 10-to-30-kilo­me­tre-long mesas are ap­prox­i­mate­ly 2000 me­tres above the sur­round­ing low­lands. This makes them about twice as tall as the fa­mous 'Ta­ble Moun­tain' in Cape Town, South Africa. The al­ti­tudes range from mi­nus 4000 me­tres (blue) to mi­nus 2000 me­tres (red). This en­tire tran­si­tion zone, which lies at about 40 de­grees north is there­fore be­low the ref­er­ence lev­el on Mars, an ‘Areoid’ (from Ares, the Greek equiv­a­lent of the Ro­man god of war Mars). The Areoid is a cal­cu­lat­ed sur­face of equal grav­i­ta­tion­al at­trac­tion, an ‘equipo­ten­tial sur­face’.
3D view of the northern part of Deuteronilus Mensae
3D view of the north­ern part of Deuteronilus Men­sae
Image 11/11, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

3D view of the northern part of Deuteronilus Mensae

Anaglyph im­ages can be gen­er­at­ed from da­ta ac­quired by the nadir chan­nel of HRSC, which is ori­ent­ed ver­ti­cal­ly on­to the sur­face, and one of the four oblique-view stereo chan­nels. When viewed with red-blue or red-green glass­es, these im­ages give a re­al­is­tic, three-di­men­sion­al view of the land­scape. North is to the right. The mesas, pro­trud­ing strik­ing­ly from the sur­round­ing plain, have been pre­served as ‘out­liers’ in the north­ern low­lands, fol­low­ing the ero­sion of the south­ern high­lands. They are ap­prox­i­mate­ly 2000 me­tres high. The im­age res­o­lu­tion of 13 me­tres per pix­el makes it pos­si­ble to ob­serve struc­tures on the de­posit­ed sed­i­ments be­tween the mesas. These pro­vide in­for­ma­tion about glacial ero­sion pro­cess­es.
  • As on Earth, glaciers and ice ages have shaped the landscape on Mars. The Deuteronilus Mensae region has evidence of glacier movements, such as mesas.
  • The lower terrain in the north and the regions between the mesas are evenly covered by deposits resembling rock glaciers found on Earth.
  • Measurements have shown that most of the glacier-like structures in Deuteronilus Mensae still contain a high proportion of pure water ice today (80 to 90 percent).
  • Focus: Space, planetary research

During ice ages on Earth, the retreating ice sheets greatly altered the landscape of the continents. Over the past two-and-a-half million years, Central Europe alone has experienced five massive glaciations. Ice from the Arctic spread as far south as Central Europe while at the same time, the kilometre-thick glaciers of the Alps pushed their way north as far as today's Danube. When the glaciers retreated during 'warm' (interglacial) periods, they typically left behind landscapes with moraines or ice age lakes. The U-shaped valleys of the Alps are evidence of this, as are the glacial erratics – rocks and stones from Scandinavia or the Alps that were carried for hundreds of kilometres on the glacial conveyor belts. Similarly, glaciers and ice ages have also shaped the Martian landscape. A particularly impressive example of this is the Deuteronilus Mensae region on the border between the southern highlands and the northern lowlands. This region is shown in these images, which were created using data acquired by the High Resolution Stereo Camera (HRSC) operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) on board ESA's Mars Express spacecraft.

The Deuteronilus Mensae region is approximately the size of Germany. It forms a striking area of the Martian dichotomy boundary, where the planetary surface transitions from the southern highlands to the lowlands of the northern hemisphere, 1000 to 2000 metres below. This boundary is characterised by numerous mesas, remnants of the erosion that reached from north to south.

Rocks carved from between the mountains were carried north

Although the valleys between these mesas were created in part by the erosive effect of flowing water, there are also numerous signs that glaciers also significantly shaped the landscape. As on Earth, glacial ice – moving very slowly and plastically under its own weight – produces a strong erosive force. The material sheared off at the bottom of the glaciers and the rocks falling onto the ice from the steep slopes at the sides of the glaciers were carried away by the glacier tongues as they advanced slowly northwards; the rocky material was also crushed by intense friction.

The fragmentation and erosion of the old highland area left behind a number of large mesas. Their plateau-like surfaces represent the remains of a land surface that once extended much further north.

The landforms indicate that there must have been several phases of glaciation. Many impact craters in the region have heavily eroded rims and have been almost completely filled by material that was carried to them and then deposited by glaciers. In some places they can still be seen as circular structures with flat bases, while in other craters only the central peak protrudes partially from the sediment (Image detail 2).

Mars ice ages in geologically recent times

The lower lying terrain in the north and the regions between the mesas are evenly covered by sediments whose surface texture suggests a slow, viscous downward movement of a mixture of debris and ice. The concentric lobate debris aprons (Image details 3 and 4) around the plateaus resemble rock glaciers or glaciers completely covered with debris, like those in cold climatic regions on Earth, such as Antarctica. The patterns formed by rubble and debris on glaciers moving down into valleys reflect the different flow velocities of the underlying viscous ice.

It is very likely that there is still ice under this carpet of rock, even if it is not visible today. Surface ice on Mars is only found in the northern and southern polar regions in the form of ice caps, and as frost on dune ridges or crater rims, where temperatures are extremely low – it is often mixed with carbon dioxide ice. In mid-latitude regions such as Deuteronilus Mensae, summer temperatures rise above zero degrees Celsius and surface water ice would normally sublimate immediately, given the low atmospheric pressure on Mars. However, if the ice is blanketed by rocky debris, it is likely that sublimation can be prevented for thousands of year.

When interpreting the structures in Deuteronilus Mensae, some scientists assume that glaciers existed here in geologically recent times – hundreds of thousands or perhaps even only 10,000 years ago – and that there could have even been ice ages similar to those on Earth. Since the obliquity of the rotational axis of Mars is thought to have changed substantially on timescales of hundreds of thousands or millions of years, different areas of the planetary surface may have been directed towards or away from the Sun. This implies that large-scale icing could also have occurred at these mid-latitudes.

This assumption is confirmed by the analysis of data from the Shallow Radar (SHARAD) instrument on board NASA's Mars Reconnaissance Orbiter, which can detect the presence of liquid or frozen water up to several hundred metres below the surface. Its measurements show that most glacier-like structures in Deuteronilus Mensae still contain a high proportion of pure water ice today (80 to 90 percent). They could thus be the remains of a supra-regional ice sheet that once covered the plateaus and adjacent plains of the region. Increasing sublimation of ice as the Martian climate changed could then have led to degradation of this extensive ice sheet, exposing the slopes of the plateaus and further eroding them. The fretted texture (Image details 4 and 8) of the lower lying areas, which can be seen to the right of centre in image 1, can be explained by downhill creep of the ice debris mixture and the resulting fracture and compression patterns.

Image processing

Systematic processing of the data acquired by HRSC took place at the DLR Institute of Planetary Research. From these data, staff in the Department of Planetary Sciences and Remote Sensing at the Freie Universität Berlin created the image products shown here. The image data were acquired by HRSC on 25 February 2018 during Mars Express orbit 17,913. The image resolution is approximately 13 metres per pixel. The centre of the images is located at approximately 25.5 degrees east and 44 degrees north. The colour image was created using data from the nadir channel, the field of view of which is aligned perpendicular to the surface of Mars, and the colour channels of HRSC. The colour-coded topographic view is based on a Digital Terrain Model (DTM) of the region, from which the topography of the landscape can be derived. The reference body for the HRSC-DTM is a Mars equipotential surface (Areoid). The oblique perspective view was generated from the DTM and data from the nadir and colour channels of HRSC. The anaglyph, which provides a three-dimensional view of the landscape when viewed using red-green or red-blue glasses, was derived from data acquired by the nadir channel and the stereo channels.

More images acquired by the High Resolution Stereo Camera can be found on DLR's Mars Express Flickr gallery.

Visit the Mars Express mission site.

The HRSC experiment on Mars Express

The High Resolution Stereo Camera was developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and built in collaboration with partners in industry (EADS Astrium, Lewicki Microelectronic GmbH and Jena-Optronik GmbH). The science team, which is headed by Principal Investigator (PI) Ralf Jaumann, consists of 50 co-investigators from 35 institutions in 11 countries. The camera is operated by the DLR Institute of Planetary Research in Berlin-Adlershof; it has been delivering high-resolution images of the Red Planet since 2004.

Contact
  • Elke Heinemann
    Ger­man Aerospace Cen­ter (DLR)
    Pub­lic Af­fairs and Com­mu­ni­ca­tions
    Telephone: +49 2203 601-2867
    Fax: +49 2203 601-3249

    Contact
  • Prof.Dr. Ralf Jaumann
    Freie Uni­ver­sität Berlin
    In­sti­tute of Ge­o­log­i­cal Sci­ences
    Plan­e­tary Sci­ences and Re­mote Sens­ing
    Telephone: +49-172-2355864
    Malteserstr. 74-100
    12249 Berlin
    Contact
  • Ulrich Köhler
    Pub­lic re­la­tions co­or­di­na­tor
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    Telephone: +49 30 67055-215
    Fax: +49 30 67055-402
    Rutherfordstraße 2
    12489 Berlin
    Contact
  • Daniela Tirsch
    Ger­man Aerospace Cen­ter (DLR)

    DLR In­sti­tute of Plan­e­tary Re­search
    Telephone: +49 30 67055-488
    Fax: +49 30 67055-402
    Linder Höhe
    51147 Köln
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